JPH0239707B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collector that can utilize solar heat and outside air heat as heat sources, and can also be used as an evaporator for heat pumps for space heating and hot water supply.

Conventionally, there are two types of solar collectors known. One of them is
The structure has an exposed evaporator as a solar heat exchange mechanism, so there is no cover such as a transparent cover on the front of the heat collecting plate, and there is no heat insulating material on the back, or there is no heat insulating material on the back. It was extremely simple and thin. The heat collecting plate is composed of a metal plate that collects sunlight and a metal tube through which a heat medium can flow, and usually an aluminum plate is used for the metal plate and a steel pipe is used for the metal tube. There are many things. Further, the aluminum plate may be a simple flat plate or a stack of many fin-like plates, and the surface of the plate is generally coated with black paint that has a high absorption rate of sunlight.

The other type is solar collectors similar to those used in solar thermal systems that operate with plain water as the heating medium. The solar heat collector includes an outer box, a transparent cover that covers the outer box, a heat insulating material provided in the outer box, and a heat collector housed in the outer box. and an outdoor coil, which is a heat exchanger on the outdoor side of a general heat pump device, that is, an outside air heat exchange mechanism, are connected in series or in parallel. The outdoor coil of the outside air heat exchange mechanism includes a fan and a fin-and-tube heat exchanger, and the heat pump device includes a heat medium compressor, a condenser, an expansion valve, and an evaporator connected in sequence. form a refrigerant circuit. Four-way valves, accumulators, various switching valves, etc. are used as necessary.

The operation, drawbacks, and problems of the above-mentioned conventional solar collector will be explained.

First, in a device that uses an exposed solar collector as an evaporator, the high-temperature, high-pressure refrigerant gas discharged from the compressor heats the indoor air and water in the hot water tank in the condenser, and is depressurized by the expansion valve to lower the temperature. It becomes a low-pressure refrigerant liquid and enters the solar collector. When there is sufficient solar radiation, the refrigerant liquid is heated by the solar heat collected by the solar collector and evaporates, turning into low-temperature, low-pressure refrigerant gas and returning to the compressor. When the amount of sunlight is low or at night, natural convection takes heat from the outside air and evaporates the refrigerant liquid.

By the way, when this exposed structure solar heat collector is used as an evaporator, the refrigerant circuit switching and control means are simple because the collector is the only evaporator, but since the collector is exposed, it is difficult to collect heat. There is a lot of heat dissipation loss during the process, and this becomes more significant as the heat collection temperature (evaporation temperature) increases. For example, if the heat collection temperature could be set 10 to 20 degrees Celsius higher than the outside air temperature, the accumulation coefficient would greatly improve, but the heat collection efficiency of bare collectors would drop sharply. In order to secure a constant amount of heat in this temperature range, a large heat collection area is required, which increases the overall cost of bare connectors, which are cheap in unit price, and requires a large installation area. Furthermore, if the heat collection temperature is lowered to about the outside air temperature, the heat collection efficiency will be greatly improved, but the accumulation coefficient will be lowered and there will be no point in using solar heat at high cost. Furthermore, when the amount of solar radiation is low, such as in the morning and evening or on cloudy days, heat is absorbed from the outside air by natural convection, so heat transfer on the surface of the heat collector plate is poor.
This also had the disadvantage of requiring a large heat collection area.

In addition, in a device equipped with an evaporator consisting of a solar collector with a transparent cover and an outdoor coil, i.e., an outside air heat exchange mechanism, the solar collector with a transparent cover is used when there is sufficient solar radiation, and the solar collector with a transparent cover is used when the solar radiation is low. , the outdoor coil is used as an evaporator to absorb solar heat and outside air heat. Note that when the amount of solar radiation is intermediate, a solar collector with a transparent cover and an outdoor coil may be used together.

Incidentally, although the evaporator of a conventional heat pump device is constructed as described above, the problem with a heat pump device that uses solar heat and outside air heat as its heat source is how to achieve low initial cost and operating cost. In general heat pump equipment that uses outside air as a heat source, the evaporation temperature is always set lower than the outside air temperature, so the coefficient of production (COP) increases as the outside air temperature falls.
becomes small, and the ratio of electrical input per capacity becomes large, making it uneconomical. The purpose of combining solar heat with a heat pump is to use solar heat to raise the evaporation temperature and significantly improve the build-up coefficient. However, since both solar heat and outdoor heat are free energy, the additional cost required to use solar heat is fully recovered during the product life due to energy savings due to an improvement in the growth coefficient, and the additional cost is more than the energy savings cost. The problem is that the relationship has to be small.

In addition, with such a combination of a solar collector with a transparent cover and an outdoor coil, the solar collector maintains a sufficiently high heat collection efficiency even if the heat collection temperature is set 10 to 20 degrees Celsius higher than the outside temperature when there is sunlight. Also, when there is no sunlight, the outdoor coil can efficiently absorb outside heat, just like a general heat pump device. However, an expensive collector and an outdoor coil must be installed separately for the evaporator, and there are also problems with the installation location, complicated refrigerant piping, control of switching valves, etc.
There were issues that needed to be resolved, such as securing the optimal amount of refrigerant.

This invention was made to focus on the above-mentioned conventional problems and to eliminate the conventional drawbacks.A fan is incorporated into the collector body with a transparent cover that collects solar heat, and the outside air is taken in and discharged. To provide a solar heat collector which can operate a heat pump device with high efficiency not only when there is sunlight but also when there is no sunlight and which is compact as a whole.

An embodiment of the present invention will be described below.

In FIGS. 1 to 4, reference numeral 1 denotes an outer box of a collector main body a that collects solar heat, and forms an outer shell. 2 is a transparent cover such as a glass plate arranged on the top surface of this outer box 1, 3 is a presser metal fitting that presses the four sides of this transparent cover 2, 4 is a waterproof gasket provided on this presser metal fitting 3, and 5 is the above-mentioned A heat insulating material is placed on the bottom and side surfaces of the outer box 1. Reference numeral 6 indicates a heat collecting plate installed above the heat insulating material 5. The inverted L-shaped fins 7 forming the main part of the heat collecting plate 6 are A large number of sheets are stacked to form the same plane. Reference numeral 8 denotes a solar heat absorbing surface constituting the upper surface of the fin 7, and an absorbing film 9 painted black is applied to the surface. Reference numeral 10 denotes an external heat absorbing surface constituting the vertical surface of the fin 7, which forms an air duct P along the longitudinal direction of the collector body a. Reference numeral 11 designates heat collection tubes made of copper tubes, which are inserted into the fins 7 in large numbers and constitute a heat collection mechanism C, and the heat collection tubes 11 are connected to each other to form a refrigerant circuit. Reference numeral 12 denotes a fan of an outside air suction/exhaust mechanism D, such as a line flow type, which is disposed at the lower bottom of the outer box 1, and the motor is omitted. Reference numeral 13 denotes a pair of outside air inlets opened at the top of the bottom of the outer box 1, 14 a pair of air outlets opened at the bottom, and 15 four mounting feet 16 provided on two sides of the outer box 1. is the mounting hole drilled in this mounting foot. A solar heat exchange mechanism A is formed by a series of structures including the transparent cover 2, the heat collecting plate 6, the solar heat absorbing surface 8 of the fin 7, and the heat collecting tube 11, and also includes the outside air heat absorbing surface 1 of the fin 7.
0, heat collection pipe 11, fan 12, outside air intake port 1
3 and the air outlet 14 form an outside air heat exchange mechanism B. Both mechanisms A and B are integrated into one collector body a.

Next, the action will be explained.

When there is sufficient solar radiation, the solar heat exchange mechanism A works and solar heat acts on the solar heat absorbing surface 8 of the heat collecting plate 6, which functions as a solar heat collector. Further, when the amount of solar radiation is low, the outside air heat exchange mechanism B works and the outside air acts on the outside air heat absorption surface 10 of the heat collecting plate 6, so that it operates as a heat collector for outside air heat. That is, when there is sunlight, the fan 12 is stopped, and the sunlight passes through the transparent cover 2 and is transmitted through the outside air heat absorption surface 10 of the fin 7 by conduction, heating the refrigerant liquid flowing in the heat collecting pipe 11 and boiling and evaporating it. Convert it to gas. Solar heat is transferred to the refrigerant in the form of latent heat, which passes through the compressor and is sent to the condenser. Note that a portion of the heat of the sunlight absorbing surface 8 is also transferred to the heat collecting pipe 11 by radiation and convection. Heat collecting plate 6
maintains high heat collection efficiency even when the evaporation temperature is higher than the outside temperature.

In addition, when the solar radiation becomes weak, the fan 1 of the outside air intake and exhaust mechanism D is activated by a sensor (not shown), for example.
2 is driven. Outside air is taken into the collector body a through the absorption port 13, passes through the air duct P between the outside air heat absorption surfaces 10 of the fins 7, passes through the fan 12, and is discharged from the outlet 14. In the process of passing through the outside air heat absorbing surface 10, the outside air is mainly absorbed from the outside air heat absorbing surface 10 into the heat collecting pipe 11, which is set at a temperature lower than the outside air temperature.

In the above embodiment, the fan 12 of the outside air suction and exhaust mechanism D was installed at the bottom of the outer box 1 to flow the air from the top to the bottom of the collector body a.
If the heat resistance of the collector body a exceeds the temperature when the collector body a is air-baked, the fan 12 is moved to the top of the outer box 1.
may be installed. In the above embodiment, the fan 12 is operated so that air is sucked into the heat collecting plate 6, but if a good wind speed distribution can be obtained, the fan 12 is set to blow air into the heat collecting plate 6. You may.

Furthermore, in the above implementation row, the air is transferred to the outside air heat absorption surface 10.
Although the air duct P is formed so that the air flows only between the transparent cover 2 and the heat collecting plate 6, it may also be made to flow between the transparent cover 2 and the heat collecting plate 6.

In addition, in the above embodiment, when collecting solar heat, the suction port 1
3 and the air outlet 14 due to natural convection, but if the suction port 13 is also equipped with an automatic damper using a motor or the like, or a damper that opens and closes using wind pressure, the heat loss can be reduced. can be further reduced. Note that as a method of reducing heat loss due to natural convection, it is also possible to install the collector main body a horizontally and arrange the inlet 13 and the outlet 14 on the left and right sides.

Figure 5 shows that outside air is sucked in by the outside air intake and exhaust mechanism D.
This shows another embodiment of the installation structure of the exhaust air duct P, in which the inlet 13 and the outlet 14 are separated by a partition plate 18 provided along the center of the collector body a placed vertically. One air duct P is provided at both ends of the lower part of the outer box 1, and a return part 17 of an air duct P obtained by cutting out the upper part of the partition plate 18 is provided at the upper part of the outer box 1. Therefore, outside air enters through the suction port 13 at the bottom of the collector body a, turns around at the return section 17 at the top, and exits again from the blowout port 14 at the bottom. The fan 12 of the outside air intake and exhaust mechanism D has an inlet 13 and an outlet 14.
It can be used for either one or both. Therefore, in the embodiment shown in FIG. 5, since the air inlets and outlets 13 and 14 are concentrated in the lower part of the outer box 1, heat loss due to natural convection can be further reduced.

In the above embodiment, a line flow type fan 12 was used to keep the collector body a thin and compact, but the same operation can be expected even if other types of fans are used.

Furthermore, in the above explanation, the present invention is applied to a heat pump device for space heating and hot water supply, but it can also be used as a condenser during cooling operation when a heat storage tank is installed and cool storage operation is performed at night in summer. Needless to say, it is available to collectors.

As explained above, according to the present invention, the reverse L
Since a large number of letter-shaped fins are erected so that their upper surfaces are on the same plane, and the upper surfaces are used as solar heat absorbing surfaces, most of the area facing the sun can be used as the solar heat absorbing surface. Since the vertical surfaces of the fins are used as external heat absorption surfaces and the fins are used as ducts during forced ventilation, heat can be exchanged efficiently.

Furthermore, when the amount of solar radiation is low, forced ventilation allows use of outside air heat, increasing the efficiency of the solar heat collector.

[Brief explanation of drawings]

FIG. 1 is a plan view of a solar collector according to the present invention, FIG. 2 is a rear view of FIG. 1, FIG. 3 is a cross-sectional view of FIG. FIG. 5 is a cross-sectional view with some lines omitted, and FIG. 5 is a rear view of a solar collector showing another embodiment of the present invention. 1... Outer box, 2... Transparent cover, 6... Heat collecting plate, 8... Solar heat absorption surface, 11... Heat collecting pipe, 12
...Fan, 13...Suction port, 14...Blowout port,
a... Collector main body, A... Solar heat exchange mechanism,
B...Outside air heat exchange mechanism, C...Heat collection mechanism, D...
Outside air intake and exhaust mechanism.

Claims (1)

[Claims] 1. A solar heat collector in which a solar heat exchange mechanism that collects solar heat and exchanges heat, and an outside air heat exchange mechanism that takes in and discharges outside air and exchanges heat with outside air heat are integrated into a collector main body, which The solar heat exchange mechanism has a plurality of inverted L-shaped fins that are erected so that their upper surfaces are on the same plane, and the upper surfaces are used as solar heat absorption surfaces. A solar heat collector characterized in that it has a heat absorbing surface and a forced ventilation means for forcing outside air to pass through the fins as a duct when the amount of solar radiation is low.